Hover over the numbered circles below to view photos and learn more about the major pieces of equipment that are included with the fourth incinerator project.
  • 1


    Thickened sludge is pumped into a dewatering centrifuge which spins at 2,600 rpm. This increases the solids concentration from 5% to 28% to a consistency like moist soil.
  • 2

    Cake Bin

    Dewatered “cake” falls into a cake bin. A sliding frame and an extraction screw conveyor feeds cake into the cake pump.
  • 3

    Cake Pump

    A hydraulically powered piston pump feeds cake through pipes to the fluidized bed incinerator.
  • 4

    Cake Receiving

    Cake receiving includes an at-grade cake bin with cake pump underneath. Cake receiving equipment will allow other facilities to haul dewatered cake to the Metro Plant as a backup, increasing the reliability of the wastewater treatment system.
  • 5

    Fluid Bed Reactor

    The cake combusts at a temperature of 1,375 degrees Fahrenheit in a bubbling sand bed. Combustion reduces the volume of cake by 95% and eliminates bacteria. The cake has enough energy that the incinerator normally burns cake without the need for supplemental natural gas fuel.
  • 6

    Primary HEX

    Hot flue gas leaving the incinerator is recovered through the primary heat exchanger to preheat the fluidizing air entering the bottom of the incinerator.
  • 7

    Waste Heat Boiler

    The waste heat boiler recovers heat from the flue gas by converting water pumped through hundreds of metal tubes into steam.
  • 8

    Secondary HEX

    The secondary heat exchanger recovers heat from the flue gas to evaporate water vapor in the stack, which removes any visible plume.
  • 9

    Carbon Tower

    Carbon is injected into the flue gas to remove mercury.
  • 10


    The baghouse uses 816 filter bags to remove particulates, which include injected carbon and heavy metals. The particles collected on the outside of the bags fall to bottom in the form of ash.
  • 11

    Wet Scrubber

    Water is sprayed into the wet scrubber to cool the flue gas and remove remaining particulates. Caustic solution is added to neutralize acid gases.
  • 12

    Wet ESP

    The wet electrostatic precipitator uses electrically charged metal rods to remove any remaining very fine particulates and heavy metals from the flue gas.
  • 13


    Emissions leaving the stack are clean, odorless, colorless, and have no visible plume.


Design is the development of drawings and specifications that will be used by a construction contractor to build a project.
workers at table
Check back here in the future for design documents.